Render on more than one computer?
You could use Sheep it it provides services for collaborative rendering.

You machines will render your own projects first.

When your machines render frames from other projects you earn credits, more credits increase the priority of your projects.

The service only accepts projects up to 500MB (including packed caches in a zip file).

the client-software can be run from a browser as Java-Applet (I had problems with the latest Java), therefore I would recommend to use the alternative to download a standalone client.

FAQ


If want to try it and would like to have working scripts to start the client, leave a message and I will add them here.
Network Render
Blender has an addon for Network Rendering in order to use it you can enable it in the User Preferences:


Manual
Web Interface
Video, tutorials